Apparatus for producing fire extinguishing foam



June27, 1939. w. FRIEDRICH I APPARATUS FOR PRODUCING FIRE EXTINGUISHING FOAM Filed Sept. 15, 1937 2 Sheets-Sheet l //////l7llflllll/I //7venz0/ W/LHELM FRIEDRICH June 27, 1939. w. FRIEDRICH 2,164,153

APPARATUS FOR PRODUCING FIRE EXTINGUISHING FOAM 2 Sheets-Sheet 2 Filed Sept. 15, 1957 Patented 'June 27, 1939 UNITED STATES PATENT OFFICE lirrana'ros FOB raonocma ma EX- rmomsnmc rem Wilhelm Friedrich, lierli'n-Charlottenburg,

Germany Application September-15,1937, Serial No. 163,905 InGermany September ,18, 1936 4 Claims. (01. zen-re) The novel device constructed according to the 1. present invention permits of the foam former being directly introduced at any point into the pressure water piping leading from the source of water under pressure, e. g. a motor pump or ahydrantto the foam generating jet pipe. By a u particular arrangement -of this intermediate mixer, there is afforded the possibility of optionally controlling or eyen fully cutting off the supply of the 'foam forming agent, for instance when, in!- stead of a foam jet, water only isto be projected.

20 The intermediate mixer constructed according to the invention essentially comprises a. suitable jet apparatus adapted to be inserted in the pressureiwater pipe, and the suction side of which can controllably be connected to a foam former 2! container. I

In order that the passage provided -for the water may be regulated in accordancewith the .amount of foam produee'dby the particular foam generator used, thel'intermediate mixer is further 30 provided with a pressure-water by-pass connected in parallel to the jetapparatus and which is I equipped with a; member adapted to adjust the cross section of passage of the bypass according to the amount of water required for foam generation within the foam jet pipe; As by varying the cross section of the water passage in the by-pass, the suction work of the jet apparatus can be in-- fiuence'd at will, thisalso affords the possibility of controlling simultaneously the supply of the $0 foam forming agent, by means ofthe shut-off device concerned. I v In the accompanying drawings the novel device is represented in several embodiments.- I

Fig. 1 shows an intermediate mixer in connection with a foam generatingjet apparatus, partly in section; a

Fig'. '2 shows partly in section.

The intermediate mixer connected to a foam another embodiment likewise '50 generator, as shown in Fig. 1, consists of a. pipe 3 adapted to-be insertedin the pressure water pipe! by means of coupling. members I land which contains ajet apparatus orejector l. The suction chamber 5 of the ejector I; is connected.

to a feeding pipe 6 for the foam forming agent 3 As illustrated the ejector 2| is arranged within which pipe can be connected to a foam former' container 6:; and is provided with a member 'I intended for thecontrol'of the foam former sup-f ply. In parallel to the ejector there is arranged a pressure-water by-pass 8 which. contains the member 9 adapted to control the passage of? water. v

The modus operandi-of the device described is as'followsz The water flowing throughthe pipe 3 and the ejector 4 draws in the foam forming I agent through thepipe 6 and while being mixed with the said foam forming agent it flows into the pipe 2 leading to the foam generator lb. The presure water stream flowing through the by-pass pipe 8 enters'the .pipe 3 as at ,l l and here it mixes with the mixture of water and foam former emerging from the ejector 4 so that a uniformly diluted solution of the foam forming agent is obtained.- The stream of the water under pressure and the supply of the foam forming agent may by the members I and 9, respectively, be controlled in accordance with the particular amounts of water'and foam former required. When instead of foam jets, a; jet of water is to be projected, the delivery of the foam forming agent may be shut off by closing the member I.

In the embodiment shown by Fig.2 the water under pressure is by-passed by a; chamber l2,

whichis formed by the pipe 3 and a shell .l3 surrounding the same. The by-passed portion of; the water iinder p through apertures I of the pipe 3 into the chamsure in this instance flows Ber. l2 and then returns'into the pipe 3 through apertures l5. For the control of the passage of water the chamber l2 contains a disc ll provided with openings it against which disc bears another disc It provided ivlthregistering openings and which is adapted, to be angularly displaced relatively to the first named disc so that the'cross section of the passage openings, It may be'modi-.

fied. The. angular displacement of thedisc I8 is e. g. accomplished by means of a bevel gear I! meshingw'ith the teeth of the disc l8 and suscep- "tible of being turned by means of a handle 20.

In order to increase the suction workof the intermediate mixer, it may be equipped with an additionalejector, into which a certain amount of the foam former is drawn-in by means of a portion branched off the water under pressure and from which the mixture of water and foam former is led into the suctionchamber of the,

ejector disposed within the main stream of the water under pressure. device, the suction thus takes place in two steps.

In the case of such av connected through an annular conduit 23 to the suction device represented here by way of example as a Venturi tube 24. The mixture of water and foam ormer as coming from the ejector 2| is drawn i through the openings 25 by the main water stream and mixed therewith as well as with the water under pressure fed through the by-pass I! and the openings v l5.

For the control oi the suction power the branch pipe 22 may be provided with a controlling member 20.

' What Lclaim is:

1. Apparatus for producing fire extinguishing loam including means for projecting a jet of water into a receiver to entrain air under substantially atmospheric pressure, and means for supplying to said projecting means water under pressure containing 10am stabilizing material, said supplying means comprising a conduit carrying water underpressure, an ejector including a nozzle and a receiver, means for by-passing a portion of the water from said conduit through said ejector to aspirate foam stabilizing solution thereby, and means connecting the receiver side of said ejector to a low pressure portion of said conduit.

2; Apparatus as defined in clainil in which 2 2,164,158 a piping I2 branched on the pipe 3 and which'is means is provided for by-passingi. a controlled quantity of water/around the low pressure portion of the conduit.

3. Apparatus for producing fire extinguishing foam by aspirating air into a liquid stream comprising a conduit carrying water under pressure and having a restricted portion in the shape of a Venturi tube, an ejector havinga nozzle and receiver, a'container for a solution of foam stabilizing material connected to the suction side of said ejector, means for by-passing water under pressure through said nozzle from a point in said conduit in advance of said Venturi tube and means connecting the receiver side of said ejector to the restricted portion of said Venturi tube.

A 4. Apparatus for producing fire extinguishing foam by aspirating' air into a liquid stream comprising a conduit carrying water under pressure 

